鲕状赤铁矿气基还原回转窑中试试验研究

Pilot Test of Gas-based Reduction Rotary Kiln for Oolitic Hematite

鲕状赤铁矿石嵌布粒度极细,而常规的选矿设备及药剂难以有效地回收,导致高品位的铁精矿很难获得。本文以宣龙式鲕状赤铁矿为研究对象,利用回转窑进行直接气基还原,采用XRD、ICP等表征手段对矿石以及铁精矿进行研究。结果表明:此鲕状赤铁矿嵌布粒度较细,为典型的沉积型铁矿。金属矿物为赤铁矿,非金属矿物主要为石英砂。在炉膛温度、给料量、还原煤气流量不变的情况下,回转窑驱动转速设定为1r/min、停留时间2h为最佳条件。矿粉原料预干燥与否对产品质量影响不大,关键是矿粉原料预干燥后进料通畅,有利于生产稳定运行。随着还原程度的增加,在精矿品位相近的情况下,铁精矿产率和回收率都在增加。

The grain size of oolitic hematite ore is extremely fine,and conventional beneficiation equipment and reagents are difficult to effectively recover,which makes it difficult to obtain high-grade iron ore.This paper takes xuanlong oolitic hematite as the research object,uses rotary kiln for direct gas-based reduction,and uses XRD,ICP and other characterization methods to study ore and iron concentrate.The results show that the ore is of sedimentary type,with fine crystal grain size and cemented material,and the structure is scale-like structure,needle-like structure,cryptocrystalline structure and metasomatic structure.the structure is mainly made of sand-like rubber structure.The metallic mineral is hematite,and the non-metallic mineral is mainly quartz sand.Under the condition that the furnace temperature,feed volume,and reducing gas flow rate remain unchanged,the best conditions are to set the driving speed of the rotary kiln to 1r/min and the residence time to 2 hours.The pre-drying of mineral powder raw materials has little effect on product quality.The key is that the raw materials of mineral powder are fed smoothly after pre-drying,which is conducive to the stable operation of production.As the degree of reduction increases,the yield and recovery rate of iron concentrates are increasing when the grades of concentrates are similar.